Grass-cutting apparatus

ABSTRACT

A plurality of circular cutters are mounted in spaced relationship on a chain, which chain is entrained on sprockets rotatably mounted in a frame. These cutters travel in a closed path adjacent the peripheral edge of a bottom plate, which edge has a plurality of teeth. Each cutter is mounted on a bracket fixed to the chain so as to be capable of rotation on its support shaft, or axle. Springs bias the cutters against the teethdefining peripheral portion of the bottom plate so that the circumferential lower edge of each cutter is adapted to cut grass in the slots defined between the teeth. Each cutter tends to rotate slowly as it travels over the bottom plate due to frictional forces between it and the bottom plate thereby presenting a continuously varying segment of its cutting edge to the grass, and also providing thereby a continuous selfsharpening cutting action.

ilnited States Patent lpbach [54] GRASS-CUTTING APPARATUS [72] Inventor:Henry E. lpbach, 55 Foxen Road, East Haven, Conn. 06512 221 Filed: Dec.14,1970

211 Appl.No.: 97,664

[ 1 Feb. 15,1972

Primary Examiner-Russell R. Kinsey Att0rneyMcCormick, Paulding & Huber[57] ABSTRACT A plurality of circular cutters are mounted in spacedrelationship on a chain, which chain is entrained on sprockets rotatablymounted in a frame. These cutters travel in a closed path adjacent theperipheral edge of a bottom plate, which edge has a plurality of teeth.Each cutter is mounted on a bracket fixed to the chain so as to becapable of rotation on its support shaft, or axle. Springs bias thecutters against the teeth-defining peripheral portion of the bottomplate so that the circumferential lower edge of each cutter is adaptedto cut grass in the slots defined between the teeth. Each cutter tendsto rotate slowly as it travels over the bottom plate due to frictionalforces between it and the bottom plate thereby presen ting acontinuously varying segment of its cutting edge to the grass, and alsoproviding thereby a continuous self-sharpening cutting action.

6 Claims, 2 Drawing Figures PATENTEDFEBIS I972 3.641.752

In yen for Henry E j ubach GRASS-CUTTING APPARATUS SUMMARY OF INVENTIONThis invention relates to grass-cutting apparatus, and deals moreparticularly with a chain having a plurality of cutters which cooperatewith a fixed plate to achieve the grass-cutting action.

A horizontally extending bottom plate is supported in a frame which maybe mounted on wheels or the like, and said plate has a plurality ofoutwardly projecting teeth or fingers between each adjacent pair ofwhichteeth an inwardly extending slot is defined. A chain is entrained oversprockets provided in the frame for movement around a closed pathadjacent to the peripheral edge of the bottom plate. A plurality ofcircular cutters are rotatably supported on the chain by means ofbrackets so that a segment of the lower circumferential edge of eachcutter travels across the teeth-defining portion of the plate.

The general object of the present invention is to provide a grasscuttingapparatus which utilizes an endless chain to carry a plurality ofself-sharpening cutters around a closed path located just inside of theperipheral edge of a fixed plate having slots to define teeth, inconjunction with which the teeth cutters cooperate to cut the grass.This construction provides a relatively safe grass-cutting apparatuswhich does not suffer from the safety hazards of the conventionalrotary-type lawnmower. The cutters are individually mounted to the chainso as to be self-sharpening in operation as they travel around a closedpath defined by the chain.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view with portionsbroken away to reveal the relationship between the cutters and the chainin an apparatus constructed in accordance with the present invention.

FIG. 2 is an elevational side view of a portion of the apparatus shownin FIG. 1.

DETAILED DESCRIPTION Turning now to the drawings in greater detail, FIG.1 shows a grass-cutting apparatus constructed in accordance with thepresent invention in a presently preferred form. A frame includes acenter portion which is generally square or rectangular in shape, andalso includes leftand right-hand portions 10a and 10b adjustablyconnected to the center portion 10 by means of outwardly extendingbrackets 12 bolted to the center frame portion 10, as indicatedgenerally by the screws 14. These screws 14 extend downwardly throughthe bracket 12 and through the center frame portion 10, and carry attheir lower ends a bottom plate 16 to be described. The upper ends ofthe screws 14 support the outwardly extending brackets 12 each of whichbrackets includes a slotted opening for adjustably receiving a secondscrew 18, which screw is adapted to adjustably mount the leftandright-hand frame portion 100 and 10b to the center frame portion 10 inthe desired relationship. The screws 14 preferably carry small idlersprockets 20 around which a chain 22 is entrained.

It will be apparent that the frame 10, or its leftand righthand portions10a and 10b, might carry suitable rollers or wheels to aid in moving theapparatus over the lawn to be cut. These conventional components areomitted for clarity, however, and from the description to follow it willbe apparent that the apparatus of the present invention might be usedeither as a single self-contained unit by the home owner, or that itmight be adapted for commercial use by providing several such devices inan installation adapted to be drawn by a single tractor or the like.

The leftand right-hand frame portions 10a and 10b each carry a sprocket,24 and 25 respectively, and these sprockets, 24 and 25, in conjunctionwith the idler sprockets 20 confine the chain 22 to the path of travelindicated generally by the series of arrows shown at 26 in FIG. 1.Either of the sprockets 24 or 25 might be driven by suitable means butin the embodiment shown each of these sprockets includes an associateddrive pulley 27 and 29 respectively, so that a plurality of thesedevices in FIG. 1 can be ganged together for use in cutting a swathwider in extent than the total width of the apparatus shown and limitedonly by the number of units which might be combined in a particularinstallation. In the conventional selfcontained lawnmower of the typeused by the homeowner a center drive shaft 30 might be driven by a smallgasoline engine or electric motor so as to operate the left-hand drivesprocket 24 through an intermediate belt 32 as shown in FIG. 1.

As best shown in the lower right-hand portion of FIG. 1 the chain 22 isof conventional construction, being continuously driven in the directionof the arrows 26 by the means described above, and as shown in this viewthe bottom plate 16 can be seen to be generally coextensive in size andextent with the overall frame defined by the portions 10, 10a and 10band the plate 16. The bottom plate 16 preferably includes outwardlyextending fingers or teeth 40 which teeth define slots or inwardlyextending openings 42 between each adjacent pair of teeth or fingers.The path of travel of the chain 22 is preferably located adjacent to andsomewhat inside of the inner ends of the slots so that cutters 44carried by the chain will travel across and above the teeth-definingportion of the bottom plate 16 in the manner to be described.

As shown, the cutters 44 are mounted in spaced relationship along theentire length of the chain 22 and each cutter is circular inconfiguration as viewed in FIG. 1, so that an outer segmentor portion ofeach cutter travels successively across each of the teeth or fingers andacross each of the associated slots defined therebetween. Moreparticularly, it will be apparent from FIG. 1 that the path of themidpoint of each ofthe circular cutters is located in closely spacedrelationship to the inner ends of the slots 42 in the bottom plate 16 sothat as the cutter travels in the direction indicated it will exhibit atendency to rotate on its support axle 46 as a result of the differencein frictional force exerted between it and the adjacent bottom plate asbetween the inside and outside half-segments of these circular cutters.

Turning now to a more complete description of the means for mounting thecutters 44 to the chain 22 said means preferably comprises an outwardlyextending bracket 48 connected at its inner end to two rollers of theconventional roller chain 22 and carrying at its outer end the supportaxle 46 for each associated cutter 44. As best shown in FIG. 2, eachcutter comprises a circular element having a vertical crosssectionalshape in the form of an isosceles trapezoid, that is having an outercircumferential side 440 which is inclined with respect to the verticaland to the horizontal lower face 44b of the cutter so as to define alower circumferential cutting edge 44a. The cutting edge 44a is moreparticularly defined by the acute angle between the circumferentiallyextending inclined side 44 of the cutter and its lower face 44b. Thesupport axle or shaft 46 associated with each of the cutters 44 islocated in centered relationship with respect to the cutter and issupported at its upper end in the bracket 48 associated with the chain22 as described above. Further, each of these support axles, or shafts46 is adapted to support its associated cutter 44 at some distance belowthe bracket 48 so as to provide a space therebetween for a coilcompression spring 50. The spring 50 provides a biasing means for urgingthe lower face 44b of the circular cutter 44 into engagement with theupper face of the support plate 16. It should be noted that each cutter44 is not otherwise supported on its associated axle 46, and as somounted each cutter 44 is free to move vertically except insofar as eachcutter is urged downwardly by the spring 50. As so constructed andarranged each such cutter 44 will exhibit a tendency to rotate as ittravels around the closed path dictated by the chain 22 so as tocontinuously present a varying segment of its periphery to the grass tobe cut, and so as to continuously exhibit a tendency to sharpen both itsown cutting edge 44a and the upper edges of the teeth slots defined bythe fixed bottom plate 6.

Iclaim:

l. A grass-cutting device comprising a frame, a horizontal bottom platesupported from said frame and having a plurality of outwardly projectinghorizontal fingers in its peripheral portion between each adjacent pairof which fingers an inwardly extending slot is defined, chain meanssupported in said frame for movement around a closed path so orientedthat a major portion of said path is located adjacent the inner ends ofsaid bottom plate slots, a plurality of cutters, means for rotatablysupporting said cutters from spaced points on said chain means, saidcutters having generally flat lower faces which engage the upper surfaceof said bottom plate in the area of said finger defining portion.

2. A grass-cutting device as set forth in claim 1 wherein each of saidcutters is circular in shape and travels around a closed path defined bythe path of said chain means, said cutter path being so oriented withrespect to said finger defining portion of said bottom plate that anouter segment of each cutter travels successively across each of saidfingers and each of said slots.

3. A grass-cutting device as set forth in claim 2 wherein each of saidcutters has an axially inclined circumferential side which cooperateswith the lower face of said cutter to define a lower cutting edge, saidcutting edge having an active segment which varies with respect to theplate as the cutter travels across each of said fingers and slots in aself-sharpening cutting action.

4. A grass-cutting device as set forth in claim 3 wherein said means forrotatably supporting said cutters from said chain means comprises anoutwardly extending bracket. the inner end of which is carried by saidchain means, a vertically oriented shaft mounted at the outer end ofeach bracket to rotatably support one of said cutters.

5. A grass-cutting device as set forth in claim 4 wherein saidcutter-supporting means further includes biasing means for urging eachcutter downwardly against said bottom plate.

6. A grass-cutting device as set forth in claim 5 wherein said biasingmeans comprises a compression spring acting between the upper surface ofsaid cutter and said cuttersupporting bracket, and spring being mountedon said cutter-supporting shaft.

1. A grass-cutting device comprising a frame, a horizontal bottom platesupported from said frame and having a plurality of outwardly projectinghorizontal fingers in its peripheral portion between each adjacent pairof which fingers an inwardly extending slot is defined, chain meanssupported in said frame for movement around a closed path so orientedthat a major portion of said path is located adjacent the inner ends ofsaid bottom plate slots, a plurality of cutters, means for rotatablysupporting said cutters from spaced points on said chain means, saidcutters having generally flat lower faces which engage the upper surfaceof said bottom plate in the area of said finger defining portion.
 2. Agrass-cutting device as set forth in claim 1 wherein each of saidcutters is circular in shape and travels around a closed path defined bythe path of said chain means, said cutter path being so oriented withrespect to said finger defining portion of said bottom plate that anouter segment of each cutter travels successively across each of saidfingers and each of said slots.
 3. A grass-cutting device as set forthin claim 2 wherein each of said cutters has an axially inclinedcircumferential side which cooperates with the lower face of said cutterto define a lower cutting edge, said cutting edge having an activesegment which varies with respect to the plate as the cutter travelsacross each of said fingers and slots in a self-sharpening cuttingaction.
 4. A grass-cutting device as set forth in claim 3 wherein saidmeans for rotatably supporting said cutters from said chain meanscomprises an outwardly extending bracket, the inner end of which iscarried by said chain means, a vertically oriented shaft mounted at theouter end of each bracket to rotatably support one of said cutters.
 5. Agrass-cutting device as set forth in claim 4 wherein saidcutter-supporting means further includes biasing means for urging eachcutter downwardly against said bottom plate.
 6. A grass-cutting deviceas set forth in claim 5 wherein said biasing means comprises acompression spring acting between the upper surface of said cutter andsaid cuttersupporting bracket, and spring being mounted on saidcutter-supporting shaft.